Embodiments of the present invention relate to hair spray compositions. More particularly, embodiments relate to compositions having a low level of volatile organic compounds.
Hair sprays are generally used to provide a temporary setting or curling effect to hair and can be removed by water or shampooing. Hair sprays typically include a hair holding agent such as a natural or synthetic resin material which is dissolved in a solvent and mixed with a propellant for delivering the product to the hair.
Typical hair holding agents include resins such as polyvinylpyrrolidone (PVP) copolymers and vinyl acetate copolymers. Typical solvents used include alcohols such as ethanol and isopropanol, which readily dissolve most resins and are compatible with a variety of propellants.
For aerosol hair sprays, hydrocarbons such as propane and butane are commonly used as propellants. Hydrocarbon propellants are useful in such compositions because they are low cost and can be liquefied under pressure. However, it is now desirable to formulate hair spray compositions with reduced levels of volatile organic compounds (VOC""s), such as ethanol, isopropanol, and other volatile materials often used in aerosol products. Most hydrocarbon propellants are designated as VOC""s. Recent government legislation has required that hair sprays contain reduced levels of VOC""s, such as 80% or 55% VOC content. For example, to meet an 80% VOC standard, it is necessary that the ethanol and most conventional propellant components comprise no more than 80% by weight of the composition. One way to lower the VOC content is to decrease the amount of ethanol in the formulation and replace it with water.
However, there are significant problems associated with the addition of water to hair spray products. These problems may include the following: (1) a decrease in resin solubility, (2) an increase in solution viscosity, (3) excessive foaming of the composition upon discharge from the container, (4) an increase in spray particle size, which causes a poor spray pattern on the hair, (5) an increase in drying time on the hair, which also leads to a more tacky feel on the hair, (6) a decrease in holding ability as humidity increases, (7) incompatibility between the solvent (water) and the propellant, which can lead to the composition separating into two phases, and (8) corrosion of the container (typically a metal can) holding the composition. These problems are generally enhanced as the water content in the composition is increased.
Several approaches have had limited success in overcoming some of the problems described above. One approach is to use resins that are soluble or dispersible within an aqueous solvent system and then add one or more suitable polymer additives for attempting to controlling the particle size and other spray characteristics of the composition. U.S. Pat. No. 5,853,700 to Gormley, et al., discloses an aqueous hair spray formulation in which conventional polymer resins are mixed with certain polypropylene oxide-modified polydimethylsiloxane block copolymers to form a hair cosmetic composition. U.S. Pat. No. 5,176,898 to Goldberg, et al., discloses an aqueous hair spray formulation containing a volatile silicone, preferably cyclomethicone or dimethicone copolyol. These approaches, however, have not solved all of the problems noted above. For example, the combination of the volatile silicone with water and conventional propellant materials yields a product having poor spray characteristics. The interactions between the additives designed to permit the use of water, the water, and the propellant materials have led to products having less than ideal characteristics.
Another approach for forming low VOC hair sprays involves using a low or non-VOC propellant such as HFC 152a, (1,1 difluoroethane, CHF2CH3) which is sold under the trade name Dymel 152a by DuPont. HFC 152a is exempt from VOC regulations due to its low photochemical reactivity. U.S. Pat. No. 5,759,522 discloses the use of HFC 152a in combination with another propellants in order to lower the VOC content. However, 152a is very expensive, so it has not achieved wide spread use and producers would prefer to find other, less expensive ways to lower the VOC content.
One embodiment of the present invention relates to a hair spray composition including a concentrate and propellant. The concentrate includes 25-45 weight percent alcohol, 30-50 weight percent methyl acetate, 5-15 weight percent resin, 0.2-1.3 weight percent neutralizer, and 5-25 weight percent water. The propellant comprises dimethyl ether. The composition includes 50 to 90 weight percent concentrate and 10 to 50 weight percent propellant.
In another aspect of embodiments of the present invention, the methyl acetate and water may together make up greater than 50 weight percent of the concentrate.
Another embodiment of the present invention includes a hair spray composition having a concentrate including 5-50 weight percent alcohol, 1-20 weight percent resin, 0.05-5.0 weight percent neutralizer, 1-50 weight percent methyl acetate, and 1-45 weight percent water. The hair spray composition includes a propellant, and the concentrate makes up approximately 50 to approximately 90 weight percent of the composition and the propellant comprises approximately 10 to approximately 50 weight percent of the composition .
Other embodiments relate to methods for manufacturing hair sprays. One such embodiment includes mixing an alcohol with a resin material to form a uniform solution. A neutralizer is mixed into the solution. Methyl acetate is mixed into the solution. Water is mixed into the solution. The solution is then combined with dimethyl ether to form a hair spray composition.